Question 20: Let ABC be a right-angled triangle with BC as the hypotenuse. Lengths of AB and AC are 15 km and 20 km, respectively. The minimum possible time, in minutes, required to reach the hypotenuse from A at a speed of 30 km per hour is
Answer: 24 Explanation: In a 3, 4, 5 triangle, the length of the altitude to
the hypotenuse = 3(4)/5 = 2.4. Therefore, in a 15,
20, 25 triangle, it is 12. This is the shortest
distance from A to BC. At 60 km/hr, i.e., 1
km/min, it would take 24 min to cover 24 km.